Re: [PATCH 25/20] sysfs: Only support removing emtpy sysfs directories.

[Eric W. Biederman]

Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:

> There's another point to consider.  If you do accept my argument that 
> empty targets can be removed from visibility regardless of the host's 
> state, then this removal races with addition of a new child.  Since 
> removal involves calling device_del(), it can't be protected by the 
> host lock.  Instead we'd have to use a mutex to protect both target 
> addition and target removal.

Careful.  Holding a lock over device_del is an easy and hidden way
to trigger a rare deadlocks.

Eric
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